Abrasive-free metal CMP in passivation domain

ABSTRACT

Metal CMP with reduced dishing and overpolish insensitivity is achieved with an abrasive-free polishing composition having a pH and oxidation-reduction potential in the domain of passivation of the metal and, therefore, a low static etching rate at high temperatures, e.g., higher than 50° C. Embodiments of the present invention comprise CMP of Cu film without any abrasive using a composition comprising one or more chelating agents, one or more oxidizers, one or more corrosion inhibitors, one or more agents to achieve a pH of about 3 to about 10 and deionized water.

TECHNICAL FIELD

[0001] The present invention relates generally to metal polishing and,particularly, to planarizing copper (Cu) and/or Cu alloy metallizationin manufacturing semiconductor devices with reduced dishing andoverpolish insensitivity. The present invention is applicable tomanufacturing high speed integrated circuits having submicron designfeatures and high conductivity interconnect structures with improvedreliability.

BACKGROUND ART

[0002] The escalating requirements for high density and performanceassociated with ultra large scale integration semiconductor wiringrequire responsive changes in interconnection technology. Suchescalating requirements have been found difficult to satisfy in terms ofproviding a low RC (resistance and capacitance) interconnect pattern,particularly wherein submicron vias, contacts and conductive lines havehigh aspect rations imposed by miniaturization.

[0003] Conventional semiconductor devices comprise a semiconductorsubstrate, typically doped monocrystalline silicon, and a plurality ofsequentially formed interlayer dielectrics and conductive patterns. Anintegrated circuit is formed containing a plurality of conductivepatterns comprising conductive lines separated by interwiring spacings,and a plurality of interconnect lines, such as bus lines, bit lines,word lines and logic interconnect lines. Typically, the conductivepatterns on different layers, i.e., upper and lower layers, areelectrically connected by a conductive plug filling a via hole, while aconductive plug filling a contact hole establishes electrical contactwith an action region on a semiconductor substrate, such as asource/drain region. Conductive lines are formed in trenches whichtypically extend substantially horizontal with respect to thesemiconductor substrate. Semiconductor “chips” comprising five or morelevels of metallization are becoming more prevalent as device geometriesshrink to submicron levels.

[0004] A conductive plug filling a via hole is typically formed bydepositing an interlayer dielectric on a conductive layer comprising atleast one conductive pattern, forming an opening through the interlayerdielectric by conventional photolithographic and etching techniques, andfilling the opening with a conductive material, such as tungsten (W).Excess conductive material on the surface of the dielectric interlayeris typically removed by chemical mechanical polishing (CMP). One suchmethod is known as damascene and basically involves forming an openingin the dielectric interlayer and filling the opening with a metal. Dualdamascene techniques involve forming an opening comprising a lowercontact or via hole section in communication with an upper trenchsection. The entire opening is filled with a conductive material,typically a metal, to simultaneously form a conductive plug inelectrical contact with a conductive line.

[0005] Cu and Cu alloys have received considerable attention as acandidate for replacing Al in interconnect metallizations. Cu isrelatively inexpensive, easy to process, and has a lower resistivitythan Al. In addition, Cu has improved electrical properties vis-a-vis W,making Cu a desirable metal for use as a conductive plug as well asconductive wiring.

[0006] An approach to forming Cu plugs and wiring comprises the use ofdamascene structures employing CMP. However, due to Cu diffusion throughinterdielectric layer materials, such as silicon dioxide, Cuinterconnect structures must be encapsulated by a diffusion barrierlayer. Typical diffusion barrier metals include tantalum (Ta), tantalumnitride (TaN), titanium nitride (TiN), titanium-tungsten (TiW), tungsten(W), tungsten nitride (WN), titanium-titanium nitride (TiTiN), titaniumsilicon nitride (TiSiN), tungsten silicon nitride (WSiN), tantalumsilicon nitride (TaSiN) and silicon nitride for encapsulating Cu. Theuse of such barrier metals to encapsulate Cu is not limited to theinterface between Cu and the dielectric interlayer, but includesinterfaces with other metals as well.

[0007] In conventional CMP techniques, a wafer carrier assembly is incontact with a polishing pad in a CMP apparatus. The wafers aretypically mounted on a carrier or polishing head which provides acontrollable pressure urging the wafers against the polishing pad. Thepad has a relative movement with respect to the wafer driven by anexternal driving force. Thus, the CMP apparatus effects polishing orrubbing movement between the surface of each thin semiconductor waferand the polishing pad while dispersing a polishing slurry containingabrasive particles in a reactive solution to effect both chemicalactivity and mechanical activity while applying a force between thewafer and a polishing pad. A different type of abrasive article from theabove-mentioned abrasive slurry-type polishing pad is fixed abrasivearticle, e.g., fixed abrasive polishing pad. Such a fixed abrasivearticle typically comprises a backing sheet with a plurality ofgeometric abrasive composite elements adhered thereto.

[0008] It is extremely difficult to planarize a metal surface,particularly a Cu surface, as by CMP of a damascene inlay, with a highdegree of surface planarity. A dense array of Cu features is typicallyformed in an interlayer dielectric, such as a silicon oxide layer, by adamascene technique wherein trenches are initially formed. A barrierlayer, such as a Ta-containing layer e.g., Ta, TaN, is then depositedlining the trenches and on the upper surface of the silicon oxideinterlayer dielectric. Cu or a Cu alloy is then deposited, as byelectroplating, electroless plating, physical vapor deposition (PVD) ata temperature of about 50° C. to about 150° C. or chemical vapordeposition (CVD) at a temperature under about 200° C., typically at athickness of about 8,000Å to about 18,000Å. CMP is then conducted toremove the Cu or Cu alloy overburden stopping on the barrier layer.Buffing is then conducted to remove the barrier layer, employing amixture of a chemical agent and abrasive particles, leaving a Cu or theCu alloy filling the damascene opening with an exposed surface.Overpolishing, as at about 10% to about 25%, is typically conductedbeyond the time required to reach the interlayer dielectric, asdetermined by conventional end point detection techniques, e.g., tocompletely remove the barrier layer. For example, if 300 seconds ofpolishing are required to reach the targeted surface, 20% overpolishingwould involve a total polishing time of 360 seconds. Conventional CMPtechniques employing polishing pads utilizing slurries containingabrasive particles as well as CMP techniques employing fixed abrasivearticles are characterized by excessive dishing sensitivity tooverpolishing.

[0009] Dishing occurs wherein a portion of the surface of the inlaidmetal of the interconnection formed in the groove in the interlayerdielectric is excessively polished resulting in one or more concavitiesor depressions. For example, adverting to FIG. 1, conductive lines 11and 12 are formed by depositing a metal, such as Cu or a Cu alloy, in adamascene opening formed in interlayer dielectric 10, e.g., silicondioxide. Subsequent to planarization, a portion of the inlaid metal 12is depressed by an amount D referred to as the amount of dishing. Forexample, dishing occurring in metal lines, such as Cu or Cu alloy metallines having a width of about 50 microns, generally exceeds 1,000Å withas little overpolish as about 5% to about 10%.

[0010] Another phenomenon resulting from conventional planarizationtechniques is known as erosion which is characterized by excessivepolishing of the layer not targeted for removal. For example, advertingto FIG. 2, metal line 21 and dense array of metal lines 22 are inlaid ininterlayer dielectric 20. Subsequent to planarization, excessivepolishing of the interlayer material results in erosion E.

[0011] Dishing disadvantageously results in a non-planar via thatimpairs the ability to print high resolution lines during subsequentphotolithographic steps. Dishing can also cause the formation of shortsor open circuits in the metal interconnection formed thereover.Moreover, dishing increases with longer overpolishing than whenoverpolishing is conducted to ensure complete removal of the metal layerand/or barrier layer across the wafer surface.

[0012] Conventional CMP techniques employ abrasives, such as anabrasive-containing slurry for use on a conventional polishing pad. Theuse of abrasives disadvantageously results in a high degree of dishingand erosion, because of pressure transmitted through the abrasiveparticle to the metal. In addition, the use of abrasives significantlyincreases the cost of consumables, as abrasives and suspension agents,as well as post CMP effluent treatment, are expensive.

[0013] There exists a need for CMP methodology enabling theplanarization of inlaid metal, particularly inlaid Cu metallization,with reduced dishing and insensitivity to overpolishing.

DISCLOSURE OF THE INVENTION

[0014] An aspect of the present invention is an efficient method ofplanarizing inlaid metals, such as Cu and Cu alloys, with significantlyreduced dishing and significantly reduced sensitivity to overpolishing.

[0015] According to the present invention, the foregoing and otheraspects are achieved in part by a method of removing at least part of amaterial, e.g., metal, from a substrate surface, the method comprisingCMP the substrate surface using a composition having a pH andoxidation-reduction potential in the domain of passivation of thematerial.

[0016] Another aspect of the present invention is a method ofmanufacturing a semiconductor device, the method comprising planarizinga deposited Cu or Cu alloy layer on a dielectric layer by CMP employinga composition comprising: one or more chelating agents; one or moreoxidizers, one or more corrosion inhibitors; one or more pH adjustingagents; and deionized water.

[0017] Embodiments of the present invention comprise CMP inlaid Cumetallization employing an abrasive-free polishing composition having apH and oxidation-reduction potential in the domain of passivation of Cuand having a low static etching rate with respect to Cu. Embodiments ofthe present invention include polishing compositions comprising one ormore chelating agents, such as ethylenediaminetetraacetic acid,ethylenediamine or methylformamide, one or more oxidizers, such ashydrogen peroxide, ferric nitrate or an iodate, one or more corrosioninhibitors, such as benzotriazole, mercaptobenzotriazole or 5-methyl-1benzotriazole, one or more acids or bases sufficient to achieve a pH ofabout 3 to about 10, such as a pH of about 5 to about 8, e.g., aninorganic and/or organic acid, the remainder deionized water.

[0018] Additional aspects of the present invention will become readilyapparent to those skilled in this art from the following detaileddescription, wherein embodiments of the present invention are described,simply by way of illustration of the best mode contemplated for carryingout the present invention. As will be realized, the present invention iscapable of other and different embodiments, and its several details arecapable of modifications in various obvious respects, all withoutdeparting from the present invention. Accordingly, the drawings anddescription are to be regarded as illustrative in nature, and not asrestrictive.

BRIEF DESCRIPTION OF DRAWINGS

[0019]FIG. 1 schematically illustrates the phenomenon of dishing.

[0020]FIG. 2 schematically illustrates the phenomenon of erosion.

[0021]FIG. 3 is a pH-oxidation/reduction potential diagram for copper.

[0022] FIGS. 4-6 schematically illustrate sequential phases of a methodin accordance with an embodiment of the present invention.

DESCRIPTION OF THE INVENTION

[0023] The present invention enables effective and efficientplanarization of inlaid metal, e.g., Cu metallization, withsignificantly reduced dishing, erosion and overpolish sensitivity,thereby avoiding the disadvantages attendant upon forming a non-planarsurface, such as a non-planar via. Such disadvantages include theimpairment of the ability to print high resolution lines duringphotolithographic processing, and the formation of voids or opencircuits in the interconnection formed thereover. Additionaldisadvantages attendant upon conventional CMP stem from the use ofabrasives, either abrasive-containing slurries or fixed abrasivearticles, which significantly increase dishing and erosion, andsignificantly increase the cost of CMP methodology. As used throughoutthis disclosure, the symbol Cu is intended to encompass high purityelemental copper as well copper-based alloys, e.g., copper-based alloyscontaining at least about 80 wt. % copper.

[0024] Aspects of the present invention are implemented by providing CMPmethodology employing a polishing composition formulated to passivatemetal films. Such polishing compositions exhibit a greatly reducedstatic etching rate, i.e., etching rate in the absence of mechanicalabrasion, even at elevated temperatures, thereby reducing dishing anderosion.

[0025] Conventional CMP methodology employs polishing compositionsrequire strong mechanic abrasive action which leads to excessive dishingand erosion. The present invention overcomes problems attendant uponhigh dishing, erosion and overpolishing sensitivity by providing CMPmethodology employing polishing compositions which form a passivationfilm over the metal surface, e.g., Cu, thereby reducing the staticetching rate. For example, conventional CMP methodology employingabrasive slurries exhibit a Cu static etching rate greater than 300Å perminute at 52° C. and greater than 730Å per minute at 52° C. for fixedabrasive copper CMP. Dishing in 50 micron conductive lines exceeds1,000Å with very little overpolish, e.g., about 5% to about 10%, due toabrasive particles.

[0026] In an embodiment of the present invention, CMP is conductedwithout an abrasive, as by employing an abrasive-free polishingcomposition with a conventional polishing pad, thereby significantlyreducing dishing and erosion, and significantly reducing the cost ofconducting CMP. Embodiments of the present invention also include CMPusing the polishing compositions containing abrasive particles or withfixed abrasive articles. Polishing compositions suitable for use inpracticing embodiments of the present invention include those disclosedin copending application Ser. No. 09/543,777, filed on Jun. 5, 2000.Such polishing compositions comprise one or more chelating agents, suchas a chelating agent containing one or more amine or amide groups, e.g.,ethylenediaminetetraacetic acid, ethylenediamine or methylformamide. Thechelating agent can be present in a suitable amount, such as about 0.2wt. % to about 3.0 wt. %. The compositions in accordance with thepresent invention further comprise one or more oxidizers, one or morecorrosion inhibitors, one or more pH adjusting agents and deionizedwater. The oxidizer or oxidizers can be any of various conventionaloxidizers employed in CMP, such as hydrogen peroxide, ferric nitride oran iodate, and can be present in a suitable amount, such as about 0.5wt. % to about 8.0 wt. %. The corrosion inhibitor or inhibitors cancomprise any various organic compounds containing an azole group, suchas benzotriazole, mercaptobenzotriazole, or 5-methyl-1-benzotriazole,and can be present in a suitable amount, such as about 0.02 wt. % toabout 1.0 wt. %. The pH adjusting agent or agents can be present in anamount for adjusting the pH of the composition to a range of about 3 toabout 10 and can comprise any of various bases or inorganic and/ororganic acids, such as acetic acid, phosphoric acid, or oxalic acid.Conventional abrasive particles can be incorporated in the polishingcomposition, e.g., in an amount up to about 10% wt. %, such as up toabout 1.0 wt. %, e.g., up to about 0.1 wt. %.

[0027] Some embodiments of the present invention comprise CMP of Cu,with or without polishing a barrier layer. In CMP of Cu, it was foundsuitable to formulate the polishing composition such that it has a pHand oxidation-reduction potential in the domain of passivation of Cu.

[0028] Conventional substrates and interlayer dielectrics areencompassed by the present invention. For example, the substrate can bedoped monocrystalline silicon or gallium-arsenide. The interlayerdielectric can comprise any of various dielectric materialsconventionally employed in the manufacture of semiconductor devices. Forexample, dielectric materials, such as silicon dioxide,phosphorous-doped silicon-glass (PSG), boron-phosphorous-doped siliconglass (BPSG) and silicon dioxide derived from tetraethyl orthosilicate(TEOS) or silane by plasma enhanced chemical vapor deposition (PECVD)can be employed. Interlayer dielectrics in accordance with the presentinvention can also comprise low dielectric constant materials, includingpolymers, such as polyamides, and carbon-containing silicon dioxide,e.g., Black Diamond dielectric available from Applied Materials, Inc.,located in Santa Clara, Calif. The openings are formed in interlayerdielectrics by conventional photolithographic and etching techniques.

[0029] Advantageously, abrasive-free CMP methodology in accordance withan embodiment of the present invention can be employed with variouscommercial polishing pads. Optimum process parameters for CMP can beeasily determined in a particular situation. For example, methodology inaccordance with the abrasivefree CMP embodiment employs a polishingpressure of about 1 to about 8 psi, and a platen speed of about 20 to120 rpm for a polishing duration of about 30 seconds to 2,000 seconds.Advantageously, the abrasive-free CMP embodiment can be employed toplanarize any of various films such as metal films, e.g., tungsten,aluminum, titanium, titanium nitride and nickel.

[0030] An embodiment of the present invention is schematicallyillustrated in FIGS. 4-6, wherein similar features bear similarreference numerals. Adverting to FIG. 4, interlayer dielectric 40, e.g.,silicon oxide, is formed overlying a substrate (not shown). A pluralityof openings 41 are formed in a designated area A in which a dense arrayof conductive lines are to be formed bordering an open field B. Abarrier layer 42, e.g., TaN, is deposited lining the openings 41 and onthe upper surface of silicon oxide interlayer dielectric 40. Typically,the openings 41 are spaced apart by a distance C which is less thanabout 1 micron, e.g., about 0.2 micron. Cu layer 43 is then deposited ata thickness D of about 8,000Å to about 18,000Å.

[0031] Adverting to FIG. 5, CMP is conducted employing an abrasive-free,noble polishing composition to remove the Cu overburden stopping on TaNbarrier layer 42, employing a conventional end point detectiontechnique, with significantly reduced dishing. As shown in FIG. 6,buffing is conducted and overpolishing, with reduced dishing.Alternatively CMP can be conducted in one stage to remove the Cuoverburden with overpolishing, using the abrasive-free noble polishingcomposition, with reduced dishing and reduced sensitivity tooverpolishing. The resulting Cu interconnection structure comprises adense array A of Cu lines 43 bordered by open field B. However, theupper surface 60 of the Cu metallization exhibits significantly reduceddishing.

[0032] The present invention is applicable to planarizing a wafersurface during various stages of semiconductor manufacturing by any ofvarious CMP techniques using any of various CMP systems and polishingarticles, e.g., fixed abrasive- or abrasive slurry-type pads or sheets.The present invention enjoys particular applicability in the manufactureof high density semiconductor devices with metal features in the deepsubmicron range.

[0033] Only the preferred embodiment of the present invention and but afew examples of its versatility are shown and described in the presentdisclosure. It is to be understood that the present invention is capableof use in various other combinations and environments and is capable ofchanges and modifications within the scope of the inventive concept asexpressed herein.

What is claimed is:
 1. A method of removing at least a part of acopper-containing material from a substrate surface, the methodcomprising polishing the substrate using a composition having a pH andoxidation-reduction potential in the domain of passivation of thecopper-containing material and comprising a chelating agentconcentration between 0.2 wt. % and about 3 wt. % of the composition. 2.The method according to claim 1, wherein the copper-containing materialcomprises copper (Cu) or a copper alloy.
 3. The method according toclaim 3, wherein the composition comprises: one or more chelating agentshaving one or more amine or amide groups, wherein the chelating agentsare selected from the group of ethylenediaminetetraacetic acid,ethylenediamine, methylformamide, and combinations thereof; one or moreoxidizers; one or more corrosion inhibitors; and deionized water.
 4. Themethod according to claim 3, wherein the composition has a staticetching rate of no greater than about 200Å per minute at about 52° C. 5.The method according to claim 3, wherein the composition has a pH ofabout 3.0 to about 10.0.
 6. The method according to claim 1, wherein thecomposition further comprises up to 0.1 wt. % of abrasive particles. 7.The method according to claim 1, wherein the method for removing atleast a part of a copper-containing material comprises planarizing adeposited copper or copper alloy layer on a dielectric layer with anabrasive-free composition having a pH and oxidation-reduction potentialin the domain of passivation of the deposited copper or copper alloylayer at a static etching rate of no greater than about 200Å per minuteat about 52° C., wherein the composition comprises: between 0.2 wt. %and about 3.0 wt. % of one or more chelating agents having one or moreamine or amide groups, wherein the chelating agents are selected fromthe group of ethylenediaminetetraacetic acid, ethylenediamine,methylformamide, and combiantions thereof; one or more oxidizers; one ormore corrosion inhibitors; a pH of about 3.0 to about 10.0; anddeionized water.
 8. The method according to claim 7, wherein planarizingthe deposited copper or the copper alloy layer on a dielectric layercomprises: forming an interlayer dielectric having at least one openingtherein over the substrate; depositing a barrier layer and the copper orthe copper alloy to fill the opening and form a layer on the interlayerdielectric; and polishing the substrate with the abrasive-freecomposition to remove the copper or copper alloy layer from theinterlayer dielectric to form a planarized surface.
 9. The methodaccording to claim 8, wherein dishing is less than about 600Å anderosion is less than about 50 Å at about 58% overpolishing.
 10. Themethod according to claim 1, wherein the composition further removesmaterials selected from the group of aluminum, tungsten, titanium,titanium nitride, nickel, and combinations thereof.
 11. The methodaccording to claim 1, wherein polishing is conducted at a pressure ofabout 1 to about 8 psi and a platen speed of about 20 to about 120 rpmfor about 30 seconds to about 2,000 seconds.
 12. A method of removing atleast a part of a copper-containing material from a substrate surface,the method comprising: chemical-mechanical polishing (CMP) the substrateusing an abrasive-free composition having a pH and oxidation-reductionpotential in the domain of passivation of the copper-containingmaterial, wherein the abrasive-free composition comprises: between 0.2wt. % and about 3.0 wt. % of one or more chelating agents; one or moreoxidizers; one or more corrosion inhibitors; and deionized water. 13.The method according to claim 12, wherein the composition furthercomprises up to 0.1 wt. % of abrasive particles.
 14. The methodaccording to claim 12, wherein the composition has a static etching rateof no greater than about 200 Å per minute at about 52° C.
 15. The methodaccording to claim 12, wherein the composition has a pH of about 3.0 toabout 10.0.
 16. The method according to claim 12, wherein the one ormore chelating agents have one or more amine or amide groups and areselected from the group of ethylenediaminetetraacetic acid,ethylenediamine, methylformamide, and combinations thereof.
 17. A methodof removing at least a part of a copper-containing material from asubstrate surface, the method comprising: forming an interlayerdielectric having at least one opening therein over the substrate;depositing a barrier layer and a copper or a copper alloy on the barrierlayer to fill the opening and form a layer on the interlayer dielectric;and chemical-mechanical polishing (CMP) the copper or copper alloy layerfrom the interlayer dielectric to form a planarized surface using anabrasive-free composition having a pH and oxidation-reduction potentialin the domain of passivation of the copper-containing material, whereinthe composition comprises between 0.2 wt. % and about 3.0 wt. % of oneor more chelating agents, one or more oxidizers, one or more corrosioninhibitors, and deionized water.
 18. The method of claim 17, wherein thecomposition further comprises up to 0.1 wt. % abrasive particles. 19.The method of claim 3, wherein the composition further comprises one ormore agents to adjust the pH.
 20. The method of claim 12, wherein thecomposition further comprises one or more agents to adjust the pH. 21.The method of claim 17, wherein the composition further comprises one ormore agents to adjust the pH.
 22. The method of claim 12, whereinpolishing is conducted at a pressure of about 1 to about 8 psi and aplaten speed of about 20 to about 120 rpm for about 30 seconds to about2,000 seconds.
 23. The method of claim 17, wherein the composition has astatic etching rate of no greater than about 200Å per minute at about52° C.
 24. The method of claim 17, wherein the composition has a pH ofabout 3.0 to about 10.0.
 25. The method of claim 17, wherein CMP isconducted at a pressure of about 1 to about 8 psi and a platen speed ofabout 20 to about 120 rpm for about 30 seconds to about 2,000 seconds.26. The method of claim 17, wherein the one or more chelating agentshave one or more amine or amide groups and are selected from the groupof ethylenediaminetetraacetic acid, ethylenediamine, methylformamide,and combinations thereof.
 27. The method of claim 12, wherein thecomposition further comprises up to 0.1 wt. % of abrasive particles. 28.A composition for chemical mechanical polishing (CMP) a surfacecontaining a metal, comprising: between 0.2 wt. % and about 3.0 wt. % ofone or more chelating agents; a pH in the domain of passivation of themetal; an oxidation-reduction potential in the domain of passivation ofthe metal; and water.
 29. The method of claim 28, wherein the metalcomprises copper (Cu) or a copper alloy.
 30. The method of claim 28,wherein the composition further comprises one or more pH adjustingagents, one or more oxidizers, one or more corrosion inhibitors,abrasive particles, and combinations thereof.
 31. The method of claim28, wherein the composition further comprises up to about 0.1 wt. %abrasive particles.
 32. The method of claim 28, wherein the one or morechelating agents have one or more amine or amide groups.
 33. The methodof claim 32, wherein the one or more chelating agents are selected fromthe group of ethylenediaminetetraacetic acid, ethylenediamine,methylformamide, and combinations thereof.
 34. The method of claim 30,wherein the one or more pH adjusting agents are an organic, inorganicacid, or combinations thereof.
 35. The method of claim 34, wherein theone or more pH adjusting agents are selected from the group of aceticacid, phosphoric acid, oxalic acid, and combinations thereof.
 36. Themethod of claim 30, wherein the one or more oxidizers are selected fromthe group of hydrogen peroxide, ferric nitrate, an iodate, andcombinations thereof.
 37. The method of claim 30, wherein the one ormore corrosion inhibitors are selected from the group of benzotriazole,mercaptobenzotriazole, 5-methyl-1-benzotriazole, and combinationsthereof.
 38. The method of claim 28, wherein the composition has astatic etching rate of no greater than about 200Å per minute at about52° C.
 39. The method of claim 28, wherein the composition has a pH ofabout 3.0 to about 10.0.
 40. The method of claim 30, wherein the one ormore oxidizers are present in a concentration between about 0.5 wt. %and about 8.0 wt. %.
 41. The method of claim 30, wherein the one or morecorrosion inhibitors are present in a concentration between about 0.02wt. % and about 1.0 wt. %.